A method for transferring data over a communication link using a data rate
and a voice modem not designed to provide communications at the data
rate, includes generating, in a processor, a modulated Frequency Shift
Keying (FSK) signal from an outgoing data stream. The voice modem, in
playback mode, plays the modulated FSK signal over the communication
link. The voice modem, in record mode, receives voice data from the
communication link and sends the voice data to the processor, which
demodulates any FSK signal that is present in the voice wave data to
produce an incoming data stream.